The present invention relates to an automatic transmission control device, and more particularly to a synchronous mesh-type automatic transmission control device for an automotive vehicle wherein, a stabilization of an operating time at changing a speed and a durability of a synchronizing mechanism are capable of being realized.
A synchronous mesh-type automatic transmission control device for a vehicle, for example, is disclosed in Japanese laid-open Patent No. 63-270252. ln this prior art, an internal combustion engine and a synchronous mesh-type automatic transmission are coupled through an electromagnetic clutch. In changing a transmission gear, a throttle opening is controlled to maintain a difference of a rotating speed of the internal combustion engine between when a electro-magnetic clutch is released and coupled within a predetermined permissible range. At the same time, a relation between the rotating speed of the internal combustion engine and the throttle opening is compensated by a learning routine program at each speed changing operation to cope with any variations of the engine characteristics and an operating condition, thus making it possible to reduce a shock when the gear is changed.
The synchronous mesh-type automatic transmission as shown in the above prior art, a pair of three position oil pressure cylinders for manipulating a shift and select lever along an axial and rotating direction are used for selecting a shift rod by driving a select three position oil pressure cylinder, for moving the selected shift rod by driving a shift three position oil pressure cylinder, and then for switching a transmission stage. In addition to the synchronous mesh-type automatic transmission driven by an oil pressure as explained above, an electric synchronous mesh-type automatic transmission with two motors for a shift and select driving operation is generally used.
In the electric synchronous mesh-type automatic transmission, a gear change operation for coupling the aimed gears is controlled in the following manner. A coupling means to be operated is selected by a select actuator while a select position is being controlled by a position signal of a select position sensor, and the coupling means is transferred for coupling the aimed gears by a shift actuator while a shift position is being controlled by a position signal of a shift position sensor. Namely, a control of the shift actuator is executed in a way, wherein the shift and select position is controlled to coincide with an aimed shift and select position by controlling a driving variable based on a deviation signal as a parameter between the aimed shift and select position and an actual shift and select position detected by the shift and select position sensor. In controlling the shift actuator and the select actuator, it is a a usual way to employ a PID control method with a position feedback, wherein P, I and D are respectively a proportional, an integral and a derivative element.
In the synchronous mesh-type automatic transmission according to the prior art, wherein a transmission gear stage is changed by controlling a shift and select position, the shift and select position are controlled to the aimed preset shift and select position. But in this prior device, as a control speed by the shift and select position was fixed, a driving feeling was not so good, and there was also a feeling of something wrong as well as a prolonged shifting time caused by a variation in an using environment, a driving condition, constitutional parts and the manipulated variable required for a shift operation due to a time lapse. Moreover, if the shift operation is fastened for reducing a time of changing the speed to cope with the above mentioned shortcomings, another problem arises, wherein a synchronizing mechanism for obtaining a synchronous rotation deteriorates in performance.
In view of the above, it is the object of the present invention to provide a synchronous mesh-type automatic transmission control device for an automotive vehicle capable of stably shortening a time for a speed changing operation and, at the same time, having a high durability.
According to this invention a synchronous mesh-type automatic transmission control device comprising
an input shaft coupled with a crank shaft of an internal combustion engine through a clutch,
a coupling mechanism including plural transmission sets, wherein each transmission set has a pair of transmission units with a different transmission ratio to each other,
a select and shift actuator for selecting one of said plural transmission sets based on a select position and for selecting one of said pair of transmission units in the selected one of said plural transmission sets based on a shift position,
an output shaft coupled with said input shaft through the selected one of said pair of transmission units in the selected one of said plural transmission sets,
a select and shift position sensor for outputting a select position signal according to said select position of said select and shift actuator and a shift position signal according to said shift position of said select and shift actuator, and
a control means for generating a driving signal varied on a rotating speed difference of said input shaft and said output shaft and for (diving said select and shift actuator by an operating speed based on said driving signal.
According to the synchronous mesh-type automatic transmission control device in this invention, as the operating speed for the select and shift actuator is configured to be varied based on the rotating speed difference between the input and the output shaft, the time required for the speed change operation is capable of being stably shortened independent of the variations in using environment, operating conditions or constitutional parts, and the control device having the synchronizing mechanism with high reliability and durability is capable of being provided.
Furthermore, the synchronous mesh-type automatic transmission control device, wherein said control means controls said operating speed so that the operating speed at the large value of the rotating speed difference is larger than the operating speed at the small value of the rotating speed difference.
According to the synchronous mesh-type automatic transmission control device in this invention, as the larger is the rotating speed difference of the input and the output shaft, the larger the shift operating speed by the select and shift actuator is controlled. Similarly, the smaller is the rotating speed difference of the input and the output shaft, the smaller the shift operating speed by the select and shift actuator is controlled. Thereby durability of the synchronizing mechanism is capable of being effectively raised.
Moreover, the synchronous mesh-type automatic transmission control device, wherein said each transmission set has a sleeve gear for selecting one of said pair of transmission units and said control means controls the operating speed of said sleeve gear according to the rotating speed difference of said input shaft and said output shaft when said sleeve gear is moved from a neutral position to the position according to said one of said pair of transmission units.
In the synchronous mesh-type automatic transmission control device according to the present invention, wherein said each transmission set has the sleeve gear for selecting one of said pair of transmission units and said control means controls the operating speed of the sleeve gear according to the rotating speed difference of the input and the output shaft. Therefore, durability of the synchronizing mechanism is capable of being promoted
In addition, the synchronous mesh-type automatic transmission control device, wherein said control means controls the operating speed of said sleeve gear so that the operating speed at the large value of the rotating speed difference is larger than operating speed at the small value of in the rotating speed difference.
Furthermore, as the operating speed of the sleeve gear is controlled to be high or low by the control means respectively depending on whether the rotating speed difference of the input and the output shaft is large or small, durability of the synchronizing mechanism is capable of being effectively promoted.